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		<h1><a href="../index.html"><img src="../docs-assets/Inform.png" height=72> </a></h1>
<ul><li><a href="../index.html">home</a></li>
</ul><h2>Compiler</h2><ul>
<li><a href="../structure.html">structure</a></li>
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<li><a href="../inblorbn.html">inblorb</a></li>
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</ul><h2>Related Projects</h2><ul>
<li><a href="https://github.com/ganelson/inweb"><img src="../docs-assets/github.png" height=0> inweb</a></li>
<li><a href="https://github.com/ganelson/intest"><img src="../docs-assets/github.png" height=0> intest</a></li>
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<p class="purpose">An overview of the core module's role and abilities.</p>

<ul class="toc"><li><a href="P-wtmd.html#SP1">&#167;1. Prerequisites</a></li><li><a href="P-wtmd.html#SP2">&#167;2. The Core</a></li></ul><hr class="tocbar">

<p class="commentary firstcommentary"><a id="SP1" class="paragraph-anchor"></a><b>&#167;1. Prerequisites.</b>The core module is a part of the Inform compiler toolset. It is
presented as a literate program or "web". Before diving in:
</p>

<ul class="items"><li>(a) It helps to have some experience of reading webs: see <a href="../inweb/index.html" class="internal">inweb</a> for more.
</li><li>(b) The module is written in C, in fact ANSI C99, but this is disguised by the
fact that it uses some extension syntaxes provided by the <a href="../inweb/index.html" class="internal">inweb</a> literate
programming tool, making it a dialect of C called InC. See <a href="../inweb/index.html" class="internal">inweb</a> for
full details, but essentially: it's C without predeclarations or header files,
and where functions have names like <span class="extract"><span class="extract-syntax">Tags::add_by_name</span></span> rather than just <span class="extract"><span class="extract-syntax">add_by_name</span></span>.
</li><li>(c) This module uses other modules drawn from the compiler (see <a href="../structure.html" class="internal">structure</a>), and also
uses a module of utility functions called <a href="../foundation/index.html" class="internal">foundation</a>.
For more, see <a href="../foundation/P-abgtf.html" class="internal">A Brief Guide to Foundation (in foundation)</a>.
</li></ul>
<p class="commentary firstcommentary"><a id="SP2" class="paragraph-anchor"></a><b>&#167;2. The Core.</b>Until 2020, the core module contained almost the entire compiler, but it is
now modularised in such a way that <a href="index.html" class="internal">core</a> itself only manages the sequence
of operations.
</p>

<p class="commentary">When <a href="../supervisor-module/index.html" class="internal">supervisor</a> decides that an Inform project is being compiled, it uses
the <a href="../words-module/index.html" class="internal">words</a> and <a href="../syntax-module/index.html" class="internal">syntax</a> modules to build a parse tree for the project and
any extensions it needs, and works out dependencies on kits of Inter code. We
don't need to deal with any of that. For <a href="index.html" class="internal">core</a>, the business starts when
<a href="../supervisor-module/index.html" class="internal">supervisor</a> calls <a href="1-wtc.html#SP3" class="internal">Task::carry_out</a>. The process is a long multi-stage one,
run as a production line: see <a href="1-htc.html" class="internal">How To Compile</a> for a detailed list of steps,
but roughly:
</p>

<ul class="items"><li>&#9679; The <a href="../assertions-module/index.html" class="internal">assertions</a> module converts top-level declarations &mdash; sentences like
"The cat is in the hat" or "A truck is a kind of vehicle", for example &mdash; into
a series of logical propositions, making heavy use of the <a href="../linguistics-module/index.html" class="internal">linguistics</a> and
<a href="../calculus-module/index.html" class="internal">calculus</a> service modules.
</li><li>&#9679; Those propositions are "asserted" as being true by the <a href="../knowledge-module/index.html" class="internal">knowledge</a> module,
which draws inferences and then reconciles these into a world model.
</li><li>&#9679; Both of those modules are helped by the <a href="../values-module/index.html" class="internal">values</a> module, which handles how
values and descriptions are parsed and then stored within the compiler.
</li><li>&#9679; Imperative code inside phrase or rule definitions is the business of the
<a href="../imperative-module/index.html" class="internal">imperative</a> module, the part of Inform most resembling a conventional compiler.
</li><li>&#9679; The <a href="../runtime-module/index.html" class="internal">runtime</a> module compiles run-time support functions and data structures
needed to make Inform's many concepts work at run-time.
</li></ul>
<p class="commentary">There are then two expansion packs, as it were: the <a href="../if-module/index.html" class="internal">if</a> and <a href="../multimedia-module/index.html" class="internal">multimedia</a>
modules, which do nothing essential but add support for interactive fiction
and for sound and images respectively.
</p>

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